Coated dry cell and process of making the same



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i i un'. ramen, orrnnrrron'r, omo, AssIGNon To narrower. enen contr m0., A CORPORATION OF NEW YORK.

eoa'r new CELL rnoenss or MAKING THE sa i application med rune so, 1919. smal No. 307,574.

To an whom z't may concern.'

Be it known that l, HARRY l". FRENCH, a citizen of the United States, 'residing at Fremont, in the county of Sandusky and State of Ohio, have invented a certain new and useful Improvement in Coated Dry Cells and Processes of Making the Same, of which the following is a full, clear, and exact description.

M invention relates to dry cells and more particularly to the `provision of a tough adherent external coating of celluloid or equivalent nitro-cellulosic material for the zine electrode, to prevent leakage when the electrolyte has eaten therethrough. v

As is well known, dry cells have a zinc can to contain the battery contents, and also to act' as the positive electrode. It is also well known that the zinc, due to a variety el causes, does not dissolve away uniformly Vthroenghout its whole surface, but corrodes cr dissolves irregularly, so that sooner or later becomes eaten through at a number ot points, which permits the leaking of the electrolyte, the admission ci air and the conseiient shortening el thelit'e of the cell.

-ry cells are' usually surrounded by a v paper jacket and when the zinc can is eaten through, this -iacket becomes wetwith the electrolyte, and it the cells are connected in series they are liable to become short circuited by the moist jackets.

lt has been proposed to paint the zinc canl with varnish, shellac, parathne and ,varions paints, Ato prevent the leaking ot' the electrolyte through the corroded parts; `but while these somewhat serve the purpose, they can Dpt/fno means be relied on to over- Y come tlrdwdiculty, as all such coatings are necessarily ot' such a character that they cannot stand much of a strain. (lonsecpuently it is .only a question et time until the` electrolyte tweaks tough the paint. varnish or other coating, to wet the jacket and 1delete the cell ol electrol.

it object et y invention is to apply aparticular-character ol coating possessing such characteristics that the leakage through the corrodedparts et thezine will be enn tirely eliminated. 'lhe manner in which this is accomplished will be explained in the appended description, and illustrated .in the annexed drawing in which the single hgure is a representation el a typical form ot my contag the improvement..

ln thedrawing the zinc can 1 contains a mix 2 consisting of the usual materials, and between the two is placed a porous orl bibulous lining 3 which may be paper, cloth or any other material that would serve the purpose. The carbon electrode 4 bearing a cap 5, and binding post 6, is located in the center of the cell with the mix packed tightly therearcund. The upper part of the cell is closed by a pitch, wax or analogous seal 7 which may be poured in a molten condition on top of adisk 8 of cardboard or4 other appropriate material. v rThe parts just described are old-and well known in the art, and my improvement consists in coating the zinc can with a tough adherent material 9 of a nitro-cellolosic ma terial having the essential characteristics of celluloid that can be placed thereon in a liquid condition and which will dry or change over into a very strong adherent waterproof coating which will retain the electrolyte when the sheet zinc is corroded throng v To apply the coating to the zinc, afsuitn able celluloid solution is formed by thinning the material known to the trade as cellu-h loid lacquer with a suitable solvent, preferably amyl acetate, `and the same is applied to the clean zinc can by painting, dipping, spraying, etc., in a suilicient amount to form the coating thereon. readily dry. by evaporation of the solvent and the celluloid will be found to stick ver tenaciously to the zinc. The ycoating au heres so tenaciously that it can be Aremoved only by inserting a thin knife blade or other instrument between it and the zinc. @om

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This coating will sequently, when this coat has once been the purpose of' the paper jacket and it would bevimpossible for unscrupulous dealers to A chasers, 'as the corrodedA spots due to shelf life or fault construction could be plainlly seen throug the transparent coating, t will be understood, nevertheless, that a dry cell that has become-corroded through at a number of places still has a great deal of life and need not be thrownaway. But when the cell ispurchased from a dealer it is supposed to be in perfect condition, and the customer naturally would not want the cell if it were evident that part of its energy had been wasted away on account of local action or other causes.

. comprising applying rectly a herent to the exterior 'surface of the sides and bottom of the container electrode.

2. Process of coating a dry cell container,

a solution of nitrocellulosic material directly to the sides and bottom of the container. l

In testimony whereof, I hereunto alix my signature.

HARRY F. VFRENCH. 

